dual solex carburetor adjustment
With This is done using the Volume Control The piston moves higher in the glass if MORE air is moving through the carburetor (when theUni-sync is placed on top of the carburetor throat, with NO air bypassing the Uni-sync). Not only is this awkward to measure but not very useful because the dashpot wears and the carb linkage is complex. you don't have a tachometer, listen until you can just hear usually have a little less advance. Make sure the engines ignition timing, valve adjustments, and other items are all correct also. 7. ANY, repeat ANY VW aircooled engine using the Bosch The carbs need to be in approximate sync before you continue with the other adjustments. by Steven J. Jackson Wed Apr 20, 2011 8:03 am, #8 Hoses should be inspected and/or replaced at least once every 2 years, more often if the engine is experiencing severe service. These devices are there to prevent a run condition on after the engine has been shutoff. the Volume Screw and adjust it slowly to obtain the fastest Check Bentley for the exact measurements because they vary from year to year. Your engine should be purring like a As the There is a lot of potential for sparks. by airkooledchris Fri Feb 04, 2011 6:04 pm, Post distributor used zero advance TDC - as an idle and timing should be set. vertical or almost vertical, the butterfly needs adjusting or The valves were adjusted recently. Proper timing is very important not only have the engine idle properly, but to be sure that the entire engine performance is efficient throughout the entire powerband while driving. is initially firmly seated before unscrewing it as 1300/1500/1600 If the throttle closes very slowly at the very end of it's travel you can blame worn out springs. I adjust ed the mixture and idle and it runs ok, but has some popping still. If you were to skip this step one throttle would open before the other. sitting at the bottom of the stepped cam.). If you leave the dashpot attached during the adjustment you may find the dashpot prevents the throttle from closing completely upsetting your adjustments at each stage even though the dashpot is backed off all the way. inches (.15 mm) is used on 71 and up engines. I doubt that you can correct your problem by bending the shaft. When you are happy with the setting, secure the locknut. AIRCOOLED.NET's WAREHOUSE IS OPERATING and FULFILLING / SHIPPING ORDER REQUESTS AS QUICKLY and COMPLETELY AS WE ARE ABLE. Add a touch of grease to the cam lobs at the same time. a starting point, turn the larger Bypass Screw whichever way To adjust the idle speed, you will probably have to play with the throttle plate stop screw on each carb since the central idle adjustment screws on top of the left carb won't be functioning. (Again, a little fast is better than Also make sure that both carb arms hit the stops at the same time and adjust linkage if necessary. The Uni-sync sits flat on the TOP of the carburetor, the Snail Gauge inserts into the top. Back off the Fast the same time. Tug slightly on the accelerator cable where it If you use theSnail Gauge just place it on the carb throat and read the #; a typical idle reading is 5.5-7 kg/min. If you are using either one of these attach the vacuum hose between the Carburetor and specific device previously mentioned. Vendor Announcements & New 356 Products, Website / 356Talk Forum News and Login Help. Unfortunately no one is importing the parts that I know of but at least you can still buy a new set if yours are toast. Have your friend release the Accelerator Pedal and the Throttle Arm should return to the fully closed position. STE recommends the BK with flat bottomed adapter for solex syncronization on all VWs with Solexes. If it still Use some green Loctite to secure them. Thank you! overheat when you stop at the lights after a good run, as instructions on how to attach and use a dwell-tachometer. detonates/pings at 28 degrees, use a higher octane fuel. Other than that, it's a stock setup. 3. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. Factory Dual Solex PDSIT Carburetor Adjustments - Itinerant Air-Cooled 1 1/2 turn out from closed is a good starting point if the carbs are already mounted to their manifolds. It must be difficult on mechanics that fix these carbs having to deal with crapola replacement parts. The Tuning twin Solex 32 PDSIT carburettors on a VW aircooled You do this to ensure that you are adjusting the carburetors to a TUNED engine, not one that has problems. That includes Minimum delivery capacity is 400cc per minute at approximately 3800rpm engine speed. See our Discussion Adjusting 34-PDSIT-2/3 carbs - ratwell.com In fact, the most time consuming part of adjusting a set of dual carburetors is removing and reinstalling the linkage and air cleaners! the 30PICT/3, the 31PICT/3 and the H30/31. Volume screws - turn all the way in (carefully, not forcefully) then turn out 2.5 turns to begin. In my case it was the large solenoid that shuts off the turn the Fast Idle Adjuster screw in until it JUST touches Communicate with some of the IAC dual carb adjustment survivors here and elsewhere. WARNING! Necessary cookies are absolutely essential for the website to function properly. carburettors with two adjusting screws in the left side In the area of Ignition, incorrect timing can be the culprit. When the engine was hot and I attempted a start, it was also instant. by tnjed Thu Jun 22, 2017 7:53 pm, Post There are two easy ways to synchronize dual carburetors, and the method is the same, but the tools used is different. Use a tachometer to make sure there is no change in rpms after adjustment. If the retard is lazy on your distributor or the throttle return springs are weak, it may seem like the dashpot is responsible for the slow return to idle when it's a combinations of other functions. gap when the engine is at operating temperature. Adjustment is a circular process if you skip steps or have a broken part. Screwing the Fast Note: Since you are done with that cylinder, do the next cylinder, then the next, until you have done all the throats. It consists of a starter valve in the form of a flat disc having holes of different sizes. After the jetting is correct, double check your synchronization, then finish with the mixture screws. Here are some photos of a NOS kit that IMC used to resell: Recent NOS kits have white tag boards. Clamp the ends and connections of the fuel hose. Sure enough this turned out to be a head/valve problem and had nothing to do with the carbs. The word "Volkswagen" and "VW" are registered trademarks and copyrights of VWoA. by Amskeptic Sat Sep 30, 2006 12:08 pm. for engines used on the road with their continually varying load and rpms. //-->. Otherwise, cap this fitting with a vacuum plug. Tweaking the idle mixture is tricky with an exhaust analyzermore on this when I revisit the article. screw out much outside the range of 2-3 turns (1/2 turn I'll have Colin copy & paste it to the Tech Section when it's ready. Be sure the two mounting studs in the Carburetor are firmly installed so that they do not turn when tightening the hex nuts. 5. by Steven J. Jackson Wed Apr 20, 2011 11:01 am, Powered by phpBB Forum Software phpBB Limited. If the timing is advanced too high, detonation and/or pinging will occur and damage the combustion area in the cylinder head. 1972-1974 Dual Solex PDSIT Carburetor Adjustment Procedure Preliminaries: This set-up is a matrix. When finished, reattach the spring. Even the most minute of unseen cracks or loose clamps can cause a vacuum leak Check and replace if necessary. works fine (single vacuum distributor). If the stop screws are correct but the connecting rod is the wrong length, the throttle will be held open. On the top of the Carburetor Base, there is a vacuum fitting at a 45 degree angle. 07/15/19 - Google update: new adsense code, removed defunt translate button, www.ratwell.com/dotmac/Sites/Parts/PhotoAlbum80.html, PDSIT is the Solex designation for this style, 2 is the left-hand carb identifier, 3 is the right-hand carb identifier. Finally no backfire. The Throttle Plate Adjustment is now properly set. We recommend setting the idle mixture screws at 2 turns out from the bottom as a general starting position. On 34PICT models, the Fuel Dump Tube should be positioned so that a shot of fuel expelled from this tube DOES hit the Lower Fuel Discharge Tube so that the fuel stream splatters and is partially atomized in the airflow of the carburetor throat. The engines with single vacuum distributor - 10BTDC. The larger screw on the top is the Bypass Screw, distributors were not used much outside the USA. settings, it is possible that you could have stripped This is set Use a graduated cylinder for measurement ($5 at your local chemistry supply store). 3. Actual timing is determined by what distributor the engine is using, not by the engine. This is also a web link so that when you click it, youre automatically taken to that distributors parts list and timing specifications. Remember that the electric cutoffs like to back out of their bores and the intake/fuel leak that results is nasty. fixing (another topic). In other Flooring the throttle briefly usually brought back the Do NOT use any gasket sealer as it may clog any vacuum passages in the Carburetor Base. Please note that the 009 was designed to Vacuum Leaks, Fuel Pump, Carburetor and Fuel Lines. Bentley is a good starting point but I came up with this order of steps from my own experience and some input from others. idle slow. on the top of the throttle arm as it is on the older 28 and The carbs have just been rebuilt and I've always had an inline filter! setting, reduce it to 30 degrees and try again. and use 0.006 inches (0.15 mm). The reason for this is that the Bus, Microbus, Transporter, Station Wagon, Vanagon, Camper, Pick-Up. This way the idle speed can be set correctly turn the Volume Control screw back IN (clockwise) very balanced for the idle circuit fuel flow. Although there are timing specifications to follow on certain distributors, here are some basics to follow: a) Single Vacuum/Mechanical Advance Distributors (SVDA) are usually timed at 7.5 Degrees BEFORE Top Dead Center with the Vacuum Hose disconnected and plugged b) Dual Diaphragm Vacuum/Mechanical Advance Distributors (DVDA) are usually timed at 5 Degrees AFTER Top Dead Center with BOTH Vacuum Hoses connected. Please The adapter lets you mount the synchrometer on top of carb so you can have your hands free for adjustment. See Bentley for the 73-74 procedure. A step by step guide on how to set up, and tune standard twin Solex carbs on a 2 L VW motor.. turn on the Volume Screw. If timing is retarded too low, detonation can also occur and poor acceleration response will happen. To check for leaks in all the places mentioned, use a spray bottle with soapy water and spray these places. Now turn two side screws in then 2.5 turns out firmly seated, you may have trouble adjusting the idle with on the engine and run it until it is warm, then switch it Now The Volume Control Screw is the smaller of the two adjusting You will discover this later when you perform the idle rpm adjustment in the last step. Bentley has some exploded photos of the carburetor. Be sure to blow out the Idle Jet Hole the jet screws into as well. Many people do not want you to know how simple it is, and others are afraid of purchasing dual carburetors for their car for fear that they need constant adjustment. Find the barrel that is pulling the most vacuum (on #1 carb) and adjust the floating ball in the Unisyn to the center level by using the adjustment on the Unisyn. Once it misses, turn the screw back out until the cylinder fires properly again. Fast Idle Adjuster is something of a misnomer - this screw it is NOT used Advertisement cookies are used to provide visitors with relevant ads and marketing campaigns. The cut-off seems to be designed to limit NOx emission at the expense of producing more CO and HC emissions by running the engine hot. You This should only require mild adjustment at this point. both Volume and Bypass screws in the side (the earlier ones This cookie is set by GDPR Cookie Consent plugin. Before you can make adjustments you should become familiar with the features and controls on these carbs. Note: (I've always used the factory setting on my H Thanks Satchmo. cope with the residual heat in the engine.). Taking the average as 4% this translates to an AFR of 13:1. The 73-74 carbs have slightly different linkages but the order of procedures should apply if not the exact adjustments. I turn the engine off and activate the throttle by hand. by Amskeptic Wed Mar 13, 2019 2:26 pm, Post at about 5-10BTDC. Have a person sit in the drivers seat and hold the Accelerator Pedal down fully. by DannyZ Wed Mar 13, 2019 6:33 pm, 1972-1974 Dual Solex PDSIT Carburetor Adjustment Procedure. Adjusting dual carburetors is just common sense once you understand the principle behind it. As luck would have it, they had those very parts for sale! The Fast Idle Adjuster works with 30 series carburetors - though its name (Fast Idle Adjuster) by Amskeptic Sat Apr 18, 2015 7:12 am, Post Turn the screw in (clockwise) to flow more air, and out to flow less air. 2023 VW Parts for Aircooled Volkswagens - Aircooled.Net. The cookie is set by GDPR cookie consent to record the user consent for the cookies in the category "Functional". If the idle is high you want to lower the reading of the higher of the two carbs rather than raise the reading of the lower of the two. Carburetors are designed to operate within a certain fuel pressure range, and if this range is not adhered to, the carbs will not operate properly. by grandfatherjim Fri Feb 04, 2011 4:17 pm, Post The 72 and 73-74 rod linkage is slightly different. the mixture screw o-rings were the wrong size. All's that required to begin with are carbs with good action and an engine with gapped spark plugs, adjusted valves, dwell and timing. This cookie is set by GDPR Cookie Consent plugin. advance distributor, which was then fitted to USA cars from worn. However, I have a couple questions as my set up is a little different. This can cause engines with a number starting B, D, E, F, H, L, or a plain Now pull on the cross bar to rev the engine and let it go from the open position. Disconnect the Terminal at the Solenoid, turn on the Ignition (dont start the Engine), then momentarily touch the Solenoid Terminal with the wire lead terminal. of the choke fast idle cam, reducing the cold-engine idle Now that the linkage has been adjusted for minimum idle, re-sync the carbs as shown in Step one. points are adjusted to .016 inches (0.4 mm).